1. Field of the Invention
The present invention generally relates to a door frame for a vehicle and method for forming the door frame.
2. Description of the Related Art
A door frame and method for forming the door frame is disclosed in Japanese Utility Model laid-open publication No. 6(1994)-32139. This door frame is formed from a single metal sheet and includes a first supporting portion, a second supporting portion and a decorative portion. The first supporting portion has a recess which supports a weather strip which seals between the door frame and a window glass. The second supporting portion has a recess which is located opposite to the recess of the first supporting portion and supports a weather strip which seals between the door frame and the vehicle body. The width of the decorative portion changes gradually along its length by tapering at one side.
One side of the decorative portion is connected to the second supporting portion via an overlapping hem portion which is formed at an edge of the sheet. The other side of the decorative portion is formed continuous with the first supporting portion. However, the door frame may rust at the edge of the hem portion. Further, the weather strip which is supported in the first supporting portion is deformed by the edge.
A method for forming this door frame includes a roll-forming step, a cutting step and a hemming step. In the roll-forming step, the sheet is bent to form the first supporting portion, second supporting portion and decorative portion. In the cutting step, one ply of a piled portion of the sheet at one side of the decorative portion is cut into a tapered shape. In the hemming step, the other ply of the piled portion of the sheet is hemmed along the cut line of the one ply. The cutting step and the hemming step together form the gradually changed width. However, the steps of forming of the door frame are complicated by the cutting step and hemming step.